i've looked at your motherboard spec and it looks very semilar to my old sabertooth so i will give this a try.

whithout knowing a lot more about the bios settings it will be vary hard to tell you exactly what is going on but it sounds like the atomatic terbo setting are not all compatable with the defalt memory settings;

so you may have to go in to the bios tweek the settings to find a set of values that the terbo can be set for that will work or you can download amd overdrive from the amd sight and do much the same thing in windows,

bare in mind that all overclocking causes more heat and unless you bought your prossessor with the water cooler option that some of them come with the stock cooler is not ment for even casual overclocking.

if you want to overclock even just to use the terbo setting you should be running software like that from afterburner that allows you to monitor and throtal both the cpu and the gpu having said that getting the most out of your rigg can be a lot of fun be carefull and read every thing you can.